1. Field of the Invention
The invention relates to a method for operating a hybrid vehicle.
2. Description of the Related Art
FIG. 1 shows a highly schematic view of a drive train scheme of a high performance hybrid vehicle, in particular of the high performance hybrid vehicle marketed by the assignee of the subject invention under the type designation “Porsche 918 Spyder Hybrid”. The drive train in FIG. 1 has two driven axles, specifically a first driven axle 10 with wheels 11 and a second driven axle 12 with the wheels 13. The first axle 10 preferably is the front axle and the second axle 12 preferably is the rear axle of the hybrid vehicle. The drive train of FIG. 1 has three power sources. The first axle 10 thus is assigned a first electric machine 14 via which the first axle 10 can be driven exclusively electrically. The second axle 12 is assigned an internal combustion engine 15 and a second electric machine 16, via which the second axle 12 can be driven. The second axle 12 can be driven either purely electrically and exclusively via the electric machine 16 assigned thereto, in a hybrid fashion via the electric machine 16 and the internal combustion engine 15, or exclusively via the internal combustion engine 15 in a purely combustion-engine-operated fashion.
According to FIG. 1, a transmission 17, which is embodied as a double clutch transmission in FIG. 1, is connected between the second axle 12 and the electric machine 16 assigned to the second axle 12. The double clutch transmission 17 therefore comprises two component transmissions 18 and 19 that are assigned respectively with clutches 20 and 21. The force flux is transmitted to the second driven axle 12 from the electric machine 16 and/or the internal combustion engine 15 either via the first component transmission 18 or the second component transmission 19 depending on which gear speed is engaged in the double clutch transmission 17. Furthermore, according to FIG. 1, a clutch 22 is connected between the internal combustion engine 15 and the second electric machine 16. The clutch 22 can be opened to decouple the internal combustion engine 15 from the second driven axle 12.
According to FIG. 1, an electrical energy store 23 and power electronics 24 interact with both the first electric machine 14 assigned to the first axle 10 and the second electric machine 16 assigned to the second axle 12. The electrical energy store 23 is discharged to a relatively high degree by the respective electric machine 14, 16 operating in the motor mode. On the other hand, the electric energy store 23 is charged to a relatively high degree by the respective electric machine 14, 16 in the generator mode.
There can also be separate power electronics and/or a separate electric energy store provided for each of the two electric machines 14 and 16.
FIG. 1 also shows a motor control device 25 and a transmission control device 26. In the exemplary embodiment shown, the motor control device 25 actuates both electric machines 14 and 16 and the internal combustion engine 15. The transmission control device 26 actuates the double clutch transmission 17. For this purpose, the control devices 25, 26 exchange data with one another and with the devices 14, 15, 16, 17 that are to be actuated or controlled.
With such a high-performance hybrid vehicle it is necessary to make available in accordance with the demand a consumption-optimized operating strategy or driving strategy, on the one hand, and an acceleration-optimized driving strategy or operating strategy, on the other. There is therefore a need for a method for operating a hybrid vehicle with which either a consumption-optimized driving strategy or operating strategy or an acceleration-optimized driving strategy or operating strategy can be made available and selected efficiently.
The invention was made in view of this need and an object of the invention is to provide a novel method for operating a hybrid vehicle.